The page of the system expressions ( https://www.scirra.com/manual/126/system-expressions ) state currently that CanvasToLayer and LayerToCanvas functions take (layer) as a parameter, in fact they take 3 parameters:
CanvasToLayerX(layer, x, y)
CanvasToLayerY(layer, x, y)
, same parameters for Layer to canvas.
Not a big issue, but since it is correctly stated in C2 itself, I might as well indicate it inside the manual.
Also an exemple for the lerp would be appreciable, since I see a lot of people using it in a non intended way (just an exemple saying if x = 0, returns a, if x=1, returns b, if x = 0.5, returns (a+b)/2 ), but it is only a suggestion (the way people are using it is to set x to a constant, and set a to lerp(a, b, x), which results in a movement towards b, slowing when approching b, never reaching b, and that leaded the community into saying sentences like "the sprite is lerping to this position", "lerp is meant to be use to do an ease in movement", which just does not make any sense, and also tends to make people think x should be multiplied by dt to be framerate independant, which won't work since x is not a time of any kind).